Re: [PATCH v2] RDMA/hns: fix return value in hns_roce_map_mr_sg

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2024/4/11 5:38, Zhengchao Shao 写道:
> As described in the ib_map_mr_sg function comment, it returns the number
> of sg elements that were mapped to the memory region. However,
> hns_roce_map_mr_sg returns the number of pages required for mapping the
> DMA area. Fix it.
> 
> Fixes: 9b2cf76c9f05 ("RDMA/hns: Optimize PBL buffer allocation process")
> Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
> ---
> v2: fix the return value and coding format issues
> ---
>   drivers/infiniband/hw/hns/hns_roce_mr.c | 15 +++++++--------
>   1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c
> index 9e05b57a2d67..80c050d7d0ea 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_mr.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_mr.c
> @@ -441,18 +441,18 @@ int hns_roce_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg, int sg_nents,
>   	struct ib_device *ibdev = &hr_dev->ib_dev;
>   	struct hns_roce_mr *mr = to_hr_mr(ibmr);
>   	struct hns_roce_mtr *mtr = &mr->pbl_mtr;
> -	int ret = 0;
> +	int ret, sg_num = 0;
>   
>   	mr->npages = 0;
>   	mr->page_list = kvcalloc(mr->pbl_mtr.hem_cfg.buf_pg_count,
>   				 sizeof(dma_addr_t), GFP_KERNEL);
>   	if (!mr->page_list)
> -		return ret;
> +		return sg_num;
>   
> -	ret = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, hns_roce_set_page);
> -	if (ret < 1) {
> +	sg_num = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, hns_roce_set_page);
> +	if (sg_num < 1) {
>   		ibdev_err(ibdev, "failed to store sg pages %u %u, cnt = %d.\n",
> -			  mr->npages, mr->pbl_mtr.hem_cfg.buf_pg_count, ret);
> +			  mr->npages, mr->pbl_mtr.hem_cfg.buf_pg_count, sg_num);
>   		goto err_page_list;
>   	}
>   
> @@ -463,17 +463,16 @@ int hns_roce_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg, int sg_nents,
>   	ret = hns_roce_mtr_map(hr_dev, mtr, mr->page_list, mr->npages);
>   	if (ret) {
>   		ibdev_err(ibdev, "failed to map sg mtr, ret = %d.\n", ret);
> -		ret = 0;
> +		sg_num = 0;
>   	} else {
>   		mr->pbl_mtr.hem_cfg.buf_pg_shift = (u32)ilog2(ibmr->page_size);
> -		ret = mr->npages;
>   	}

In the above, can we replace the local variable ret with sg_num? So the 
local variable ret can be removed.
A trivial problem.

@@ -433,7 +433,7 @@ int hns_roce_map_mr_sg(struct ib_mr *ibmr, struct 
scatterlist *sg, int sg_nents,
         struct ib_device *ibdev = &hr_dev->ib_dev;
         struct hns_roce_mr *mr = to_hr_mr(ibmr);
         struct hns_roce_mtr *mtr = &mr->pbl_mtr;
-       int ret, sg_num = 0;
+       int sg_num = 0;

         mr->npages = 0;
         mr->page_list = kvcalloc(mr->pbl_mtr.hem_cfg.buf_pg_count,
@@ -452,9 +452,9 @@ int hns_roce_map_mr_sg(struct ib_mr *ibmr, struct 
scatterlist *sg, int sg_nents,
         mtr->hem_cfg.region[0].count = mr->npages;
         mtr->hem_cfg.region[0].hopnum = mr->pbl_hop_num;
         mtr->hem_cfg.region_count = 1;
-       ret = hns_roce_mtr_map(hr_dev, mtr, mr->page_list, mr->npages);
-       if (ret) {
-               ibdev_err(ibdev, "failed to map sg mtr, ret = %d.\n", ret);
+       sg_num = hns_roce_mtr_map(hr_dev, mtr, mr->page_list, mr->npages);
+       if (sg_num) {
+               ibdev_err(ibdev, "failed to map sg mtr, ret = %d.\n", 
sg_num);
                 sg_num = 0;
         } else {
                 mr->pbl_mtr.hem_cfg.buf_pg_shift = 
(u32)ilog2(ibmr->page_size);

Zhu Yanjun

>   
>   err_page_list:
>   	kvfree(mr->page_list);
>   	mr->page_list = NULL;
>   
> -	return ret;
> +	return sg_num;
>   }
>   
>   static void hns_roce_mw_free(struct hns_roce_dev *hr_dev,